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When to Plant Microgreens in Iron County, WI

Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Iron County, Wisconsin is in USDA Zone 3b. The average last spring frost is May 22 and the first fall frost is September 25, giving you a growing season of approximately 126 days.

At an elevation of 841 feet, Iron County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78ยฐF, so choose short-season varieties of Microgreens to ensure they mature before fall.

Iron County, WI (Zone 3b) Short season
126 days
Last Spring Frost May 22
126 growing days
First Fall Frost September 25

Iron County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: May 25 – Jun 22
Recommended (50%) ✓ Fits season (91 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: May 29 – Jun 26
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Apr 25 Transplant: Jun 6 🍅 Harvest: Jun 13 – Jul 11

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Microgreens needs ~119 GDD — county provides 1,071 GDD Excellent fit

Microgreens Planting Timeline โ€” Iron County, WI

Microgreens Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 15 May 15 โ€“ Jun 5
Fall Sowing July 3 Jul 3 โ€“ Jul 17
Harvest May 29 May 29 โ€“ Jun 26

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow Harvest
June Transplant Outdoors Direct Sow Harvest
July Fall Sowing
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

7โ€“21 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 3b

Growing Season

126 days

Growing Tips for Iron County

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Iron County, WI?

Iron County is in Zone 3b with an average last frost of May 22. Plan your Microgreens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Iron County, WI?

Iron County, Wisconsin is in USDA Hardiness Zone 3b. The average last spring frost is May 22 and first fall frost is September 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Iron County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Iron County, WI. Local conditions may vary. Last updated: April 2026.